1. Field of the Invention
The present invention relates to a liquid crystal display device, and more particularly to a backlight unit that reduces leakage current.
2. Discussion of the Related Art
Generally, a liquid crystal display devices are widely used due to its characteristics of light weight, thin profile, low power consumption, etc. As a result, the liquid crystal display device is used in office automation equipment, audio/video equipment, etc. The liquid crystal display device controls the amount of light in accordance with a signal applied to a plurality of control switches that are arranged in a matrix, thereby displaying a desired picture on a screen.
In this way, the liquid crystal display device is not a self luminous display device, thus it requires a separate light source such as a backlight.
Backlights may be classified as a direct type and an edge type in accordance with the location of a light source. The edge type backlight has a light source installed at the edge of one side of a liquid crystal display device, and the edge type backlight irradiates light from the light source to a liquid crystal display panel through a light guide panel and a plurality of optical sheets. The direct type backlight has a plurality of light sources disposed directly under the liquid crystal display device, and the direct type backlight irradiates light from the light sources to the liquid crystal display panel through a diffusion plate and a plurality of optical sheets.
Recently, the direct type backlight which has improved brightness, light uniformity and color purity versus the edge type backlight, is more often used in LCD TVs.
The direct type backlight has a side support which supports a plurality of lamps and is electrically connected to the electrode of the lamps, as shown in FIGS. 1 and 2.
Referring to FIGS. 1 to 2, the side support includes an upper side support 100 into which a plurality of lamps 106 are inserted; and a lower side support 102 which is assembled with the upper side support 100 with the lamps 106 therebetween.
The lamps 106 may be EEFL's where an external electrode 106A is formed.
The upper side support 100 includes an inclined plane that is inclined to the lamps 106, and a lamp insertion groove 104 formed at the lower end of the inclined plane.
The lower side support 102 is manufactured so that its cross section is L-shaped. At an inner side surface of the lower side support 102, a common electrode 108 is installed for supplying a drive AC voltage to an external electrode 106A of the lamps 106.
The common electrode 108 is connected to a plurality of metal clips 110 that cover the external electrode 106A of the lamp 106 and is attached to the lower side support 102 so as to face the side and bottom surfaces of the lower side support 102.
However, in the direct type backlight unit using this side support, there is a problem in that a large leakage current is generated because of a high capacitance between the common electrode 108 and the external electrode 106A of the lamp 106.